Artificial fingertip senses textures and sends signal to arm amputee who has neural interface implanted.
Restoration of touch after hand amputation is a desirable feature of ideal prostheses. Here, we show that texture discrimination can be artificially provided in human subjects by implementing a neuromorphic real-time mechano-neuro-transduction (MNT), which emulates to some extent the firing dynamics of SA1 cutaneous afferents. The MNT process was used to modulate the temporal pattern of electrical spikes delivered to the human median nerve via percutaneous microstimulation in four intact subjects and via implanted intrafascicular stimulation in one transradial amputee. Both approaches allowed the subjects to reliably discriminate spatial coarseness of surfaces as confirmed also by a hybrid neural model of the median nerve. Moreover, MNT-evoked EEG activity showed physiologically plausible responses that were superimposable in time and topography to the ones elicited by a natural mechanical tactile stimulation. These findings can open up novel opportunities for sensory restoration in the next generation of neuro-prosthetic hands.
Now, the hardware used is somewhat staggering:
- PC (computer) a few kg
- multichannel interface, 2,8 kg
That does not yet cover any additional weight for battery, socket, wrist connector and prosthetic hand.
But, hey ; )
Ultimately, I can not agree with the authors just now. They conclude that:
"The promising results obtained with microstimulation in four intact subjects, combined with robust translational indications from the hybrid model and an excellent outcome from one amputee, prompt the idea that neuromorphic stimulation could be a natural and effective tool for eliciting texture discrimination abilities via hand prostheses"
More stuff on an already overweight idea.
I wish, from the bottom of my heart, for Calogero Maria Oddo, Stanisa Raspopovic, Fiorenzo Artoni, Alberto Mazzoni, Giacomo Spigler, Francesco Petrini, Federica Giambattistelli, Fabrizio Vecchio, Francesca Miraglia, Loredana Zollo, Giovanni Di Pino, Domenico Camboni, Maria Chiara Carrozza, Eugenio Guglielmelli, Paolo Maria Rossini, Ugo Faraguna and Silvestro Micera, to wear the following setup for 24 months, 14 hours a day, 5 days a week:
- sandpaper directly on skin of arm
- a few rocks or pepper as well
- then tightly wrap hand and arm with neoprene
- then add 2 kg of weight around the wrist
- then add their hardware (at least 4 kg) to the torso anywhere
- limit range of motion for elbow and wrist
- seriously limit hand function
- wear a sub mm thin silicone glove that costs 700 CHF / item; making each replacement a dedicated single task of at least 2 hours (simulate real life drama when a prosthetic "bionic" hand glove tears up);
Carry that out for the specified time (my suggestion is totally realistic, though really 5 years without break would be better). For that time I do not want to read one single Twitter complaint (nothing I invented either: that is how companies such as Touchbionics treats their customers: you get treated the authoritarian top-down arrogant way, if you complain about clearly faulty produce, they let you know a complaint is not in order).
- evaluate possible depression
- evaluate possible skin deterioration
- evaluate possible shoulder, arm and back problems
Maybe after that ordeal they understand my choices. Actually I am sure it requires that experience for them to understand. Others manage with empathy, some require the full footwork.